arXiv subjects

F. Monroy

Publications and source records attributed to F. Monroy.

7 recordsLinked to original sources

arXiv2026

Mass Generation from Embedding Geometry in Surface Nematics

We show that a nematic field constrained to a curved embedded surface develops an emergent geometric mass in its leading isotropic interaction sector. An auxiliary embedding-space closure mediated by the surface spin connection yields a massive scalar mode $\chi_n$ with mass set by the extrinsic curvature invariant $m^2=K_{ab}K^{ab}$. This mass arises directly from embedding geometry, promoting the intrinsic massless nematic interaction into a geometry-controlled massive field. The resulting theory identifies Gaussian curvature as a distributed geometric charge and establishes embedding geometry as the regulator of defect interactions on curved nematic membranes.

cond-mat.soft↗

arXiv2026

Renormalized flow theory of wave turbulence: Kolmogorov-Zakharov spectra as emergent asymptotic states

We develop a continuous Wilsonian renormalized-flow theory of weak wave turbulence directly in spectral frequency space, for finite cascades in experimentally driven Newtonian fluids. The central quantity is a scale-dependent effective coupling that governs nonlinear transfer across logarithmic frequency shells and organizes the cascade as a finite renormalized branch. Within this formulation, the inertial interval is constructed dynamically as a plateau of the running flow, whose non-autonomous character is expressed through its explicit dependence on the logarithmic distance from the injection scale and thereby encodes the cumulative action of forcing and degradation along the cascade. The ultraviolet cutoff follows internally as the terminal scale at which the plateau branch ceases to exist, whereas the integrated spectral response is fixed by infrared matching to the injection scale. In this way, the finite inertial branch is determined by the renormalized dynamics itself, while Kolmogorov--Zakharov (KZ) spectra arise only as its asymptotic constant-flux scaling states. The theory applies to both capillary and gravity wave turbulence and admits a physically transparent realization in monochromatically driven discrete cascades, which fix the topology-dependent exponent structure of the renormalized flow.

physics.flu-dyn↗

arXiv2023

Variance Sum Rule for Entropy Production

Entropy production is the hallmark of nonequilibrium physics, quantifying irreversibility, dissipation, and the efficiency of energy transduction processes. Despite many efforts, its measurement at the nanoscale remains challenging. We introduce a variance sum rule for displacement and force variances that permits us to measure the entropy production rate $\sigma$ in nonequilibrium steady states. We first illustrate it for directly measurable forces, such as an active Brownian particle in an optical trap. We then apply the variance sum rule to flickering experiments in human red blood cells. We find that $\sigma$ is spatially heterogeneous with a finite correlation length and its average value agrees with calorimetry measurements. The VSR paves the way to derive $\sigma$ using force spectroscopy and time-resolved imaging in living and active matter.

physics.bio-ph↗

arXiv2022

The role of spontaneous curvature in the formation of cell membrane necks

The mechanical effects of membrane compositional inhomogeneities are analyzed in a process analogous of neck formation in cellular membranes. We cast on the Canham-Helfrich model of fluid membranes with both the spontaneous curvature and the surface tension being non-homogeneous functions along the cell membrane. The inhomogeneous distribution is determined by the equilibrium mechanical equations, and, in order to establish the role played by the inhomogeneity, we focus on the catenoid, a surface of zero mean curvature, which can be described in terms of the catenary curve parameterized by arc length. We show that analytic solutions exist for the spontaneous curvature, as well as for both, the surface tension and the radial elastic force. An analytic expression for the constrictive force at the neck, is obtained. From the energetic analysis, it is found that, if we fix the value of the constrictive force at the neck, the set of solutions lies on two branches separated by an energetic barrier. This barrier corresponds to the energy of the maximum catenoid. If instead we fix the axial force, the solution has access to catenoid of any size

cond-mat.soft↗

arXiv2019

Mechanics of nematic membranes: Euler-Lagrange equations, Noether charges, stress, torque and boundary conditions of the surface Frank nematic field

The mechanics of a flexible membrane decorated with a nematic liquid-crystal texture is considered in a variational framework. The variations on the splay, twist and the bend energy of the nematics are obtained from the local deformations leading to changes in the shape membrane. The Euler-Lagrange derivatives and the Noether charges are identified from the variational equations. The nematic stress tensor is obtained as a consequence of translational invariance. Likewise, the rotational invariance implies the torque nematic tensor. The corresponding boundary conditions are obtained for free edges in the open-membrane configuration. These results constitute the basis of a generalized theory of elasticity for anisotropic nematic membranes. Some relevant consequences of the presence of nematic ordering are visualized at revolution surfaces with axial symmetry.

cond-mat.soft↗

arXiv2019

Universality classes of surface wave turbulence as probed by laser Doppler velocimetry in viscous fluids

By taking advantage of laser Doppler velocimetry (LDV), we explore the existence of discrete wave cascades on fluid interfaces excited upon monochromatic excitation. We study viscous liquids of variable capillarity spanning a broad range of frictional stresses. The existence of an inertial regime of weak surface wave turbulence (weak-SWT) has been pointed out as a cascade of discrete modes with amplitudes compatible with universal Kolmogorov`s scaling. The transit from weak to strong surface turbulence has been explored with this tool revealing the importance of inertia over surface forces to describe the crossover.

physics.flu-dyn↗

arXiv2019

Membrane stress and torque induced by Frank's nematic textures: A geometric perspective using surface-based constraints

An elastic membrane with embedded nematic molecules is considered as a model of anisotropic fluid membrane with internal ordering. By considering the geometric coupling between director field and membrane curvature, the nematic texture is shown to induce anisotropic stresses additional to Canham-Helfrich elasticity. Building upon differential geometry, analytical expressions are found for the membrane stress and torque induced by splaying, twisting and bending of the nematic director as described by the Frank energy of liquid crystals. The forces induced by prototypical nematic textures are visualized on the sphere and on cylindrical surfaces.

cond-mat.soft↗